The present invention relates to an anomaly judgment system for an operator detection device, more particularly to a system that judges normality/anomaly of an operator detection device in an industrial vehicle.
Unexamined Japanese Patent Publication No. 2004-176570 discloses an anomaly diagnosis system that diagnoses the anomaly of a seat switch as an operator detection device which is disposed in an operator's seat. The seat switch is provided for executing warming-up of an element related to an engine prior to start of the engine. Based on turning the seat switch from an OFF state into an ON state, it is detected that the operator is seated, thereby to determine that the engine will be started soon. When an OFF signal is not obtained from the seat switch in spite of determining that the operator gets off the vehicle, the anomaly of the seat switch is detected. Additionally, when the anomaly state continues for a predetermined time period after the detection of the anomaly, the seat switch is diagnosed as final anomaly.
It is determined that the operator gets off the vehicle when confirming all of the following facts; that an ignition switch is in an OFF position; that an ignition key is drawn from an ignition insertion switch; that a door is opened and closed; and that door-lock is executed from an outside of the vehicle. Input of information on the above facts is required. Namely, in order to determine that the operator gets off the vehicle, it is required to respectively determine whether the ignition switch is in the OFF position, whether the ignition key is drawn from the ignition insertion switch, whether the door is opened and closed, and whether the door-lock is executed from an outside of the vehicle. Thus, the diagnosis system is made complicated and diagnosis logic is made complicated.
The anomaly of the seat switch is detected only when it is determined that the operator gets off the vehicle. Additionally, the seat switch is diagnosed as final anomaly when the anomaly state continues for a predetermined time period after the detection of the anomaly. However, when it is misjudged that the operator gets off the vehicle and the operator is actually seated for the predetermined time period or more, even though the seat switch actually works in a normal manner, the seat switch is diagnosed as final anomaly.
The present invention is directed to an anomaly judgment system for an operator detection device which precisely judges anomaly of the operator detection device with a simple structure.